package com.ustcinfo.study.mr.wangqiangqiang;

import java.io.IOException;

import com.ustcinfo.study.mr.sg.MyWorldCount;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
/**
 * @author wqq
 * @ClassName: MyWorldCount
 * @Description
 */
public class MyWorldCount2 {
	//map过程
	private static class MyMapper extends Mapper<Object,Text,Text,IntWritable>{
		private static final IntWritable count=new IntWritable(1);
		//每次读一行
		protected void map(Object key,Text value,Context context) throws IOException, InterruptedException{
			String line=value.toString();
			String[] arr=line.split(" ");
			for(int i=0;i<arr.length;i++){
				Text word=new Text();
				word.set(arr[i]);
				context.write(word, count);
			}
		}
			
	}
	//reduce过程，相同的key使用同一个reduce处理
	private static class MyReducer extends Reducer<Text,IntWritable,Text,IntWritable>{
		protected void reduce(Text key,Iterable<IntWritable> values,Context context) throws IOException, InterruptedException{
			int sum=0;
			for (IntWritable val : values) {
				sum+=val.get();
			}
			context.write(key, new IntWritable(sum));
		}
	}

	public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
		 Job job = Job.getInstance();
		 job.setJobName("wqq_word_count");
	     job.setJarByClass(MyWorldCount.class);
	     job.setMapperClass(MyMapper.class);
	     job.setCombinerClass(MyReducer.class);
	     job.setReducerClass(MyReducer.class);
	     job.setOutputKeyClass(Text.class);
	     job.setOutputValueClass(IntWritable.class);
	     FileInputFormat.addInputPath(job, new Path(args[0]));
	     FileOutputFormat.setOutputPath(job, new Path(args[1]));
	     int status = job.waitForCompletion(true) ? 0 : -1;
	     System.exit(status);   

	}

}
